The present invention relates to an electronic still camera, and in particularly, to an electronic still camera wherein an image obtained through an image pickup lens is received by a solid image pickup element, and a still image thus obtained is handled as digital data.
There has been developed an electronic still camera wherein an image is converted to an electric signal by the use of a solid image pickup element to be recorded as an electric signal. An electronic still camera of this type is spreading due to its handiness that it is rapid in reproduction and image processing can also be done, thus an improvement in image quality of the electronic still camera has been desired.
In the case of an electronic still camera in prior art, there has been a big problem with regard to image quality that a false image is generated due to the relation between an interval of adjoining pixels (pixel pitch) of a solid image pickup element and a resolving power of an image pickup lens.
To solve this problem, occurrence of the false image is prevented by arranging an optical low-pass filter between an image pickup lens and a solid image pickup element as described in TOKKAIHEI 7-92430, or by giving a function of an optical low-pass filter to an image pickup lens, or by eliminating a high frequency component which is higher than a critical resolving power determined by a pixel pitch as described in TOKKAISHO 64-917.
As stated above, in the case of an electronic still camera, image quality has been improved by adding an optical low-pass filter to a conventional lens.
Though the resolution has been determined depending on the number of pixels (or pixel pitch), on the other hand, it has been difficult to obtain image quality higher than that obtained by preventing a false image, because components of a specific frequency or higher than that are eliminated as stated above.
For a recent demand for the higher image quality, the technologies mentioned above are not sufficient to obtain satisfactory images, as stated above.